A bad quality render while it took over 12 hours to render
I think denoising might be the issue here. It looks like too much of it. I would turn it off. It's best to test rendering small regions in areas that you suspect might be more noisy before the final render(ctrl+b to define a region, ctrl+alt+b to clear). You may find that you do not need that many samples if you test it. 20 000 - 30 000(not squared) is usually enough even for scenes with difficult mostly indirect lighting. You might need a lot less than that to get your scene noise free. I would also check the camera's Depth of Field settings and make sure everything you wish in focus is actually in focus. The resolution is also quite low - some might consider the resolution of 580 by 884 pixels 'bad quality'. That's only slightly bigger image than passport photos usually are if you think about it.